Q. My shower stall was renovated with ceramic tile three years ago. Is it too late to seal the grout? Also, one grout joint in a corner has cracked, from the floor to the ceiling. How can I fix it so it won’t crack again?

CHRISTINE

JOHNSTON,

Wilmington

A. You can seal the grout the day after you applied it or 100 years later. If it isn’t dirty, seal all three sides of the shower with a tile sealer or masonry sealer. That will make the grout water-resistant, if not waterproof, and help prevent the growth of mold and dirt. If it is dirty, clean thoroughly with bleach and water, rinse, and seal. Any of the clear masonry or tile sealers will work; resealing will be necessary.

As for the grout in the corner, it cracked because it was not compacted heavily enough. The corner is a bigger pain than the flat surfaces because there is often a bigger empty space behind. Dig out all the old grout with a utility knife or any sharp instrument. Buy unsanded grout and insert it in the crack with a squeegee; press it in so that it is completely compact. Then smooth off and forget about it until a day or two later when you can seal it.

I am not a big fan of using caulking with ceramic tile, but this particular corner may be just the place for it. You can try it, anyway; put a bead of adhesive caulk (Phenoseal and Polyseamseal are two good brands) in the corner, then press it in and smooth it off.

Q. The apartments in my building have very big windows, and wide sills too. The sills are covered by two rows of ceramic tiles, and they get mortal cold. How can I insulate those tiles in my apartment?

CHILLY

A. Those cold tiles might be pulling air right down the windows and sill, and can actually create a draft, even in a tight house. Try this: Buy several carpet tiles, the thicker the better, and cut them to fit on the sills, then glue the parts on the sill with an adhesive caulk. Tell your neighbor how to do it and you will come out a hero.

Q. I have steam heat, and my cellar is really, really hot. How can I cool it off and/or utilize that wasted heat?

SWEATING!

A. If all the pipes leading to and from the boiler are bare, you can insulate them with a special compressed fiberglass insulation. Check the boiler as well. It may be insulated, but if the insulation is white and sort of hanging off the boiler, leave it alone; that is asbestos and it can be a serious hazard to occupants if loose and friable, but it can be encapsulated by an asbestos specialist. A well-insulated boiler and pipes will save you a lot of heat, keeping it in the pipes and radiators upstairs. If the pipes are asbestos wrapped, and the wrap looks in bad shape, it must be encapsulated or removed by a specialist, then reinsulated with the aforementioned compressed fiberglass. Also, check all valves at the top end of all radiators, to make sure they are working right.

Sometimes you can utilize the heat by installing vents in the first floor, but if there is any free asbestos in the cellar, this is not a good idea. Insulating all the pipes and the boiler is your best bet.